We conducted a statistical analysis of charts on FertilityFriend.com to find out if the average temperature just after ovulation (before a pregnancy test would turn positive) has any correlation with the chance of pregnancy.
We also ran a subsequent study to find out if the size of the temperature rise has any direct bearing on the chance of pregnancy.
The conclusion for both cases is that we do not see any direct correlation. It is well possible that pregnancy may be more influenced by other factors.
The immediate post-ovulation temperature is related to the level of progesterone secreted by the corpus luteum. Progesterone is needed to prepare the lining of the uterus for implantation of a fertilized egg. These physiological reasons may lead you to wish for high temperatures and a large rise, however it may not be the deciding factor in most cases.